Effect of selected biostimulants on the yield and quality of the common onion (Allium cepa L.)

A field experiment was conducted in 2017-2018 in the Agricultural Experiment Station owned by the University of Warmia and Mazury in Olsztyn. The experiment had a randomized block design with three replications. The first experimental factor was a number of common onion cultivars: ‘Whitney Wing F1’, ‘Spirit F1’ and ‘Red Baron’. The second experimental factor was the effect of two plant growth biostimulants; Calleaf Aminovital and Maximus Amino Protect, on the yield and quality of the onions. In the control treatment, plots were sprayed with water. The total yield, marketable yield and the marketable yield as a percentage of the total yield, the weight, vertical diameter and horizontal diameter of each onion bulb, the content of dry matter, total sugars, reducing sugars, L-ascorbic acid and nitrates (V) in the onions were determined in the study. The evaluated cultivars differed significantly with regard to the weight and size of the onions. Onions of cv. ‘Whitney Wing F1’ were characterized by a greater yield, and the weight, vertical diameter and horizontal diameter of the bulbs were all higher than they were for the remaining cultivars. The concentrations of dry matter, total sugars, L-ascorbic acid and nitrates (V) were higher in cv. ‘Red Baron’. The contents of L-ascorbic acid and nitrates (V) were significantly affected by the application of biostimulants, and the effects were more pronounced for onions treated with Maximus Amino Protect. The interaction between the experimental factors had a significant effect on the weight of individual onion bulbs, and on the concentrations of dry matter and L-ascorbic acid in the edible plant parts.